Two-dimensional light-receiving devices are widely used as an imaging device. This type of imaging device includes pixels defined by photoelectric conversion portions two-dimensionally arranged in a semiconductor, and singles produced in the pixels by photoelectric conversion are transferred as charges and read out by a CCD circuit or a CMOS circuit.
A photodiode including a photoelectric conversion portion containing an organic compound has been known.
PTL 1 discloses a highly sensitive, fast-response organic photoelectric conversion element with a high S/N ratio of light current to dark current. The organic photoelectric conversion element includes a hole blocking layer containing a fullerene derivative and an organic compound having an ionization potential of 5.5 eV or more.
In the organic photoelectric conversion element disclosed in PTL 1, the holes generated from the photoelectric conversion layer do not efficiently reach a hole-collecting electrode. Thus, this organic photoelectric conversion element has room for improvement.